This invention pertains to containers for protecting electrical storage batteries against being damaged when several of them are stacked as is the case when they are put on a pallet for being shipped or being stored.
Typically, the terminal posts of a storage battery extend higher above the plane of the top of the battery case than do the terminal interconnecting straps and the filler caps. Hence when batteries are stacked without having suitable spacers between the top of a lower one and the bottom of the next upper one, the terminal posts of the lowest one in the stack would bear the full load of those above it and would likely be deformed or otherwise damaged. With the load being concentrated on the terminal posts rather than distributed over a larger area on top of the case, the internal elements of the battery may be damaged also by force transmitted from the terminal posts.
Many container designs have been proposed for preventing the load from being concentrated on the terminal posts or on the filler caps or terminal straps when batteries in the containers are stacked. U.S. Pat. No. 2,779,527 is one example. It discloses a one-piece corrugated paperboard container which has flaps extending integrally from one pair of opposite side walls. The flaps have parallel score lines which define sections that are folded or bent reentrantly, that is, downwardly and then upwardly to provide a shoulder at the bend which bears on top of the battery case close to its edge to accept the vertical load. The reentrantly bent flap sections interface with each other so the width of the shoulder is equal only to two thicknesses of the paperboard out of which the container is made. The reentrantly bent and interfaced flap sections carry all of the load. The reentrantly folded flaps have a tendency to unfold and can easily do so until another pair of cover flaps are locked with them.
Another prior battery container is disclosed in U.S. Pat. No. 3,056,536. It also uses the reentrantly bent and interfacing flap section concept to define a narrow shoulder that bears on the top of the battery case to accept the load. In this patent, there are cover flaps that are bent horizontally from opposite vertical side walls so they fit tightly between the reentrantly bent flap sections that define the shoulders. This prevents the sections that define the shoulders from unfolding but, again, the cover flaps do not do this until the container is finally closed. As in the case of the previously discussed patent, this patent has the disadvantages of concentrating the load on narrow shoulders, a tendency for the double-folded sections that define the shoulders to open, and the absence of any additional support for the top of the container for distributing some of the load over areas of the battery case top other than its edges.
Another prior art storage battery container is disclosed in U.S. Pat. No. 2,578,107. In this patent, a flap extending from each of an opposite pair of said walls has four parallel score lines which allow the sections of the flap between the score lines to be folded in a closed-loop fashion to define a hollow beam, or cushion as it is called, which bears on the top of the battery case to accept the vertical load. One of the problems perceived in this design is that the reentrantly folded flap sections which form the beam must be perforated so as to enable forming a notch in the sides of the beam for allowing the beam to clear a filler cap or terminal post when the container is placed on a battery. The notch must be quite large so significant weakening of the beam results. Moreover, because of the score lines in the flap for forming the beam being straight or parallel, the beam sections are likely to have a tendency to unfold. In addition, as is illustrated in this patent, the beams or cushions do not bear exclusively on the top of the battery case but could bear on the lead straps that connect the battery cells in series.